Bladed servers are comprehensive computing systems that include processors, memory, network connections and associated electronics, all on a single motherboard called a blade. This high-density technology addresses the current trend among large computing centers to reduce space requirements while lowering their total cost of ownership. A server blade, along with storage, networking and other blades, are typically installed in a rack-mountable enclosure that houses multiple blades that share common resources such a cabling, power supplies and cooling fans.
In the design and manufacture of electronic components, it is common to perform testing to help detect or identify material, process and design weaknesses of the components. Such testing is desirable as it helps ensure the delivery of high-quality and reliable products to the end consumer.
One common test is frequency margin testing of the CPU (central processing unit) or bus (also referred to as runway) clock inputs. A component may work satisfactorily at nominal clock frequencies, but a dip or rise in the frequency or amplitude may cause a marginal component to fail. Such dips or rises are a part of normal operating conditions due to such factors as electromagnetic interference or line noise, drift or loss of reference clocks, or variations in components.
Frequency margin testing is generally accomplished using automated tester equipment to provide a variable external clock input. Often, these stationary testers are expensive, with some as much as $40,000 each. Additionally, such stationary testers are generally impracticable in the field.
For the reasons stated above, and for other reasons stated below that will become apparent to those skilled in the art upon reading and understanding the present specification, there is a need in the art for alternative apparatus and methods for frequency margin testing of bladed servers.